(1) Field of the Invention
The subject of the invention is a contacting device for monitoring a support means in an elevator installation.
(2) Description of Related Art Including Information Disclosed under 37 CFR 1.97 and 1.98
In many items of transport equipment, for example elevator installations, escalators, moving walkways, hoists or cranes, use is made of belt-shaped support means. These support means generally comprise several tensile carriers which consist of steel wires and which accept the tension forces to be absorbed by the support means. The tensile carriers are usually surrounded by a casing of plastics material. The casing protects the tensile carriers at least partly from mechanical effects. In addition, the casing improves the traction of the support means on deflecting or drive rollers and fixes the arrangement of tensile carriers relative to one another.
The support means are a safety-critical component within transport equipment. The failure or breakage thereof can in the extreme case lead to, for example, dropping down of a car together with the passengers therein. This can lead to considerable harm to objects and persons. For this reason, use is made in transport equipment of check units which, in particular, check the mechanical state of the tensile carriers. Damage to the tensile carriers accepting the forces shall thereby be able to be recognized in good time so that the support means can, in the case of damage, be exchanged in order to prevent failure of the transport equipment.
The tensile carriers are surrounded by an electrically insulating casing of plastics material. In order to carry out a check of the state of the tensile carriers, contacting of a contact element with the tensile carriers is required in some procedures. In a known procedure a current serving as a test current determining the state of the tensile carriers is conducted through the tensile carriers with the help of the contact element. Apart from that, other test methods which do not operate with electrical current, for example ultrasound, also come into consideration.
DE 39 34 654 A1 shows a support means forming the category. The ends of the tensile carriers are in that case conductively connected in pairs with a bridge part so that the tensile carriers of the support means are electrically connected in series. The tensile carriers of the support means are connected with a voltage source by way of an ammeter so that the state of the tensile carriers can be assessed by means of the test current which is conducted through all tensile carriers due to the electrical connection in series.
DE 2 330 038 shows a system for contacting a flat cable. In the illustrated flat cable several strands are arranged adjacent to one another within a plane and are surrounded by a casing. For electrical contacting of the strands the flat cable is clamped in place by an upper and a lower clamping member. Arranged at the lower clamping member are recesses through which prongs formed at a contact carrier can be guided. The prongs thereby penetrate the casing of the flat cable and thus come into contact with the strands. Contacting of the strands by means of the prongs thus takes place perpendicularly to a longitudinal axis of the strands. It is disadvantageously required with this contacting that the prongs penetrate the casing of the support means. Penetration of the casing by the prongs can, however, have the consequence that the prongs during penetration of the casing depart from the intended direction of insertion and as a result contact with the strand cannot be produced. The prongs can thus possibly also contact other, undesired strands or even contact no strands at all during penetration of the casing.
WO 2005/094249 A2 and WO 2006/127059 A2 show a system for contacting a support means in which the contact elements initially puncture the casing of the support means perpendicularly to a longitudinal axis of the tensile carriers and then penetrate into the tensile carriers. Disadvantageously, in that case the contact elements due to the required puncturing process through the casing can miss the tensile carriers.